1. Field of the Invention
The disclosures herein generally relate to a treatment liquid application apparatus.
2. Description of the Related Art
Image recording of an inkjet method is becoming increasingly popular these days because of its advantage that colorization can be easily realized, in addition to its advantages of low noise and low running cost. But, when an image is formed on a recording medium which is a non-manufacturer-specified paper, problems related to initial image quality such as image blur, image concentration change, color tone change, image show-through, etc., occur. In addition, problems related to robustness of images such as water resistance, weather resistance, etc., occur.
On the other hand, in the Patent Document 1 and the Patent Document 2, for example, configurations are proposed in which treatment liquid that has a function to cause the ink to aggregate is applied to a recording medium before the process of ejecting ink droplets onto the recording medium.
In the configurations disclosed in Patent Document 1 and Patent Document 2, however, it is assumed that a cut sheet is used as a recording medium, and the disclosures disclosed in Patent Document 1 and Patent Document 2 do not include a configuration in which treatment liquid is applied to an elongated recording medium such as a continuous paper.
In the meantime, in the case of applying treatment liquid on the elongated recording medium, it is essential to take into account a problem of slack of the recording medium. The slack occurs at a stopping of conveyance of the recording medium.
Slack of an elongated recording medium is a phenomenon which is caused, when a roller including a driving source is stopped, by a roller (which does not include a driving source) which is located in the upstream side with respect to the roller including the driving source, and continues the rotation because of inertia.
Here, if the conveyance starts without removing the slack, the result is that a strong enough tension is not provided for the recording medium at the time of re-start. And, in this situation, if the recording medium is pressed onto an application roller in order to apply treatment liquid to the recording medium, the recording medium sticks to the application roller in the case where the viscosity of the treatment liquid is high or the recording medium is thin. As a result, a failure, such as a failure in which the recording medium gets rolled around the application roller, may happen.
For the above reasons, in the case where the treatment liquid is applied to the elongated recording medium, it is desirable that the recording medium is controlled in such a way to be pressed onto the application roller after an appropriate tension is applied to the recording medium.
[Patent Document 1] Japanese Patent Application Publication No. 2002-096452
[Patent Document 2] Japanese Patent Application Publication No. 2002-103583